When a chiropractor adjusts a person, the goal is to get joints moving properly. Because we are talking about movement, the force equation comes into play: Force = Mass x Acceleration. So, in order to adjust, a chiropractor needs mass and acceleration. If there is not enough mass, they need enough acceleration and vice versa. In general, the greater the acceleration, the more comfortable the adjustment.
There are a number of reasons a quick adjustment is preferable. Most people guard to some degree when getting adjusted. It is a natural response. Guarding only gets worse when someone tries to increase the force by increasing mass because the body is aware of the force. Along those same lines, an adjustment when someone is guarding doesn’t always move the joints thoroughly enough which leads to an unsatisfied feeling that there is still something not moving correctly. In addition, the nerve sensors of a joint, known as the proprioceptors, need to be stimulated to get the full benefit of an adjustment. The only way to do that is with a quick movement of the joint.
Everybody is different in how they interpret comfort. Some like a firm touch others gentle. Some like to hear the cracking sound and some do not. Regardless of preference, thorough movement of joints is critical for a proper adjustment. Whether the speed is achieved through skilled hands, an adjusting tool like the Activator, or a drop table, the quicker the movement, the less mass and the less trauma on the body.